Method for detecting leaks in a tank system

ABSTRACT

The invention relates to a method for preparing models of technical devices, wherein each technical device comprises units that are connected to each other by means of connection point, wherein, when performing the method, at least one structure made of units connected to each other by means of connection points comprising commonalities for all technical devices is integrated and automatically described as at least one common module ( 8 ) for all models.

The invention relates to a method for preparing models, a method for diagnosing at least one technical device, a device for preparing models, a computer program and a computer program product.

STATE OF THE ART

At modern motor vehicles the functionality is mostly provided by software. The spectrum reaches thereby from the engine control up to comfort systems, a computer architecture that is based on that is construed as distributed system. Depending on the type of motor vehicle there are 20 to 80 control unit knots, which are connected with up to four different bus systems. A program code comprises thereby several hundred thousand up to several million lines. Such connectivity in a motor vehicle will constantly increase in the upcoming years, in addition to the increasing complexity of hydraulic, pneumatic and mechanic motor vehicle components as well as an increasing variety of motor vehicle types. For these reasons the error search and correcting in an auto shop is significantly exacerbated.

During the service at an auto shop the considered diagnosing strategy is of a symptomatic nature, which means a certain amount of symptoms of a malfunction, which usually arise from three diagnosing information sources, is the initial point for the auto shop diagnosis:

-   -   information, which arises from an online diagnosis from the         control unit diagnosis     -   information from physical measurement parameters during an         offline diagnosis, for example: voltage, pressure, exhaust gases         etc.     -   information from subjective observations of the auto shop         personnel, for example noises, visual control etc.

Nowadays there are different diagnosing tools, which support the personnel in the auto shop at the error search. Advanced systems are based on algorithms of a class of the model-based diagnosis. These algorithms analyze all available diagnosis information and compare them to a functional model of the motor vehicle. Due to the functional model the behavior of the motor vehicle is mirrored up to a certain detail degree. The models are thereby usually construed hierarchically, which means there are models of components, which illustrate the model of a subsystem in its relay, several subsystems models create models of systems, for example breaking system, engine system etc., the amount of all system models subsequently creates the model of the motor vehicle.

Due to the comparison of the actual behavior of a motor vehicle with the modeled behavior model-based diagnosing algorithms are able to provide recommendations for suspicious components or also additional measuring and control demands.

DISCLOSURE OF THE INVENTION

The invention relates to a procedure for preparing models and therefore for modeling a number of technical devices, whereby it is provided, that each technical device provides units, which are connected with each other over connecting points, whereby at least one structure of units that are connected with each other over connecting points, which provides commonalities for all technical devices, is summarized and automatically described as at least one common module for all models of the technical devices when implementing the procedure.

The at least one common module is therefore automatically described for all models and therefore the number of the technical devices.

In a configuration the described commonalities are extracted over the connecting points or the connecting knots or the so called ports. Furthermore these commonalities can be construed identically for all technical devices. The units provide internal connecting points or ports within a module, over which the units are connected with each other within the module. External connecting points or ports of the module or of the units, which are in particular arranged at the border of the module, qualify for creating connections to units outside of the module.

At a further configuration of the procedure it is provided that at least one structure, which provides at least one unit with at least one connecting point, which is present for at least one technical device and which distinguishes itself from the at least one common module, is described as at least one variant of a model for the at least one technical device within the number of the technical devices, whereby at least one difference of the variant is extracted, so that overall commonalities and variant specific details or differences of the technical devices can be extracted.

The at least one common module is usually construed as maximally coherent common or identical structure for all devices. With the procedure and particularly with the models a behavior of the technical devices can be described. By providing common modules a behavior, which appertains to or shares a variety or if necessary all technical devices, for this variety of technical devices can be considered comprised and therefore as identical for all these devices. A behavior, which appertains to one device or only a few devices, can be described by units outside of common modules, so that these units describe special or specific variants of individual modules.

It is provided amongst others that interactions between the units are described with the connecting points. Furthermore a hierarchy of the units is described in the course of the procedure. Units, which are construed in a lowermost component of technical devices, are thus for example summarized in the nearest higher level as subsystems and such subsystems in the nearest higher level as systems and systems subsequently as models of technical devices. Common modules of several technical devices can summarize common structures, which can comprise units, subsystems as well as systems.

At least one structure of units that are connected with each other over connecting points, which provides commonalities for a subset of the technical devices or which is construed identically, is automatically described as at least one module for the subset or as partial module of the technical devices in one variant of the invention.

The procedure qualifies for example for technical units that are similar to and related with each other, for example motor vehicles of one production series with different motorizations or equipments. By providing common modules units are modeled under consideration of connecting points summarized for all motor vehicles. Differences between the motor vehicles, which can be contingent on different equipments amongst others, are considered within the range of the procedure as variants. Within the structures, which can be modeled as common or variant specific modules, connecting points mirror coherences between individual units within such structures. The described connection points or knots are either described as internal or external ports. A first internal connection point at a first unit within a structure and/or a module can thereby connect or link this first unit with a second unit, which provides a second connection point. So-called external ports or connecting points are usually construed module-overlapping and can connect a module with another module or another unit.

The commonalities and differences, if present, of the technical devices are extracted due to the described construction of structures and/or modules. Thus the structures or modules comprise groups of units.

At least one group of units, which provides a common or identical structure for all devices, can also be described as one common abstract summarized for all devices, whereby at least one unit, which distinguishes itself from the units of the at least one group, is described as one additional variant to the abstract for at least one device. Therefore the abstract can be described depending on a coherent structure of the units of the at least one group.

Even hierarchies of units of the technical devices can be described with the models. It is thereby provided amongst others that individual components of technical devices are described as simplest or most elementary units. Depending on the structure individual components and thus units can be summarized as modules, which are also called sub-systems, depending on how they are connected to each other. Such sub-systems on the other hand can be called units, which can be again summarized as systems while considering connecting points, which also create common or if necessary different modules for the technical devices.

It is provided that the technical devices can be described modularly with the aid of the described procedure. Common or identical modules, which provide commonalities for all technical devices or at least a part of the technical devices or which are construed identically, are called abstracts amongst others, with which a modular modeling of the technical devices is possible, so that by a summarized consideration of a number of technical devices, which are summarized by the abstracts, for example during an application a diagnosis of at least one technical device is possible.

All technical devices can provide at least one group of common characteristics, besides at least one of these devices can provide at least one characteristic that is different from the common characteristics or units, so that the at least one group of common characteristics is described as an abstract, and at which the at least one different characteristic or one different unit for the at least one device is described as additional variant to the at least one abstract. It is also possible to have two or several groups of common characteristics or units. With the invention a metric for structure similarities of components is considered amongst others. The described variants can be based on the same basics.

The invention furthermore relates to a procedure for diagnosing at least one technical device, which comprises several units and which is assigned to a number of technical devices, whereby the diagnosis is carried out with the aid of a model for the at least one technical device, which is described by a procedure according to one of the previous claims.

Thus also a summarized consideration of all technical units is possible while considering the provided models, because now available commonalities can be considered over the common modules for all devices together.

The device for providing models of technical devices, whereby it is provided that each technical device provides units, which are connected with each other over connecting points, is construed for automatically describing at least one structure of units, which are connected with each other over connecting points, which provide commonalities for all technical devices, as at least one common module for all technical devices.

This described device is amongst other construed to carry out all steps of at least one of the previously described procedures, which means of the procedure for providing models of the technical device as well as the procedure for diagnosing at least one technical device.

The computer program with program means is construed to carry out all steps of a described procedure, if the computer program is carried out on a computer or a corresponding arithmetic unit, in particular in a described device.

The invention furthermore relates to a computer program product with program code means, which are stored on a computer readable data carrier, in order to carry out all the steps of the suggested procedure, if the computer program is carried out on a computer or a corresponding arithmetic unit, in particular a device according to the invention.

The invention furthermore provides modeling mechanisms in order to be efficient for the given variant variety of the invention, and to enable a simple connection of already available models by using common modules, in order to create a basis for a system-overlapping diagnosis.

Thus aspects for a modeling language are usually provided by the invention. During an application the invention can be used for carrying out a model-based diagnosis for at least one technical device.

The models are usually in a hierarchic structure, components are thereby summarized as smallest units in sub-systems or modules as bigger units. Within the systems, which can also be construed as modules, sub-systems are again summarized.

Considering the variant variety it is possible with the invention to extract commonalities of technical devices and therefore of models with the modeling mechanisms in order to create automated modules or so-called abstracts. An abstract is typically a module, which provides only the commonalities of several technical devices, for example a basic construction of a diesel system for a motor vehicle type of one series, which applies for all variants. An abstract can therefore serve as a model for a number of variants. This results in the fact that by using an abstract for all variants or technical devices a part of the model is already available as a concrete and only the variant specific details are modeled out and therefore concretized as additional units, for example a turbo charger of a diesel system with a turbo charger. A hierarchic order of the abstracts is also possible, which means abstracts, which provide commonalities themselves, can again be abstracted further and thereby summarized.

The modeling effort can be reduced with the invention. Furthermore a reusability of existing modules, for example abstracts for variants or for newly developed systems, is given.

At a system-overlapping diagnosis a relay of partial systems of a module or abstract is possible. The foundations of the relay are for example interface, which are called ports. With the invention these special ports can be provided in order to enable a function assignment as internal or external port.

A relay of partial systems with each other can thereby furthermore be realized, in particular also by connecting systems. Together with the so-called black box procedure, a used modeling language, a system-overlapping diagnosis is enabled, without having to develop all components in detail, whereby for example only the external connecting points of sub-systems or modules but not the units, which are summarized in such sub-systems or modules, are considered in this context, just like at a so-called black-box.

The black-box procedure is a common mechanism, which allows to model sub or partial systems without making accurate statements about the internal structure. Only the entire behavior, for example if air of the amount A flows in air of the amount of B has to flow out, and the external ports of the sub or partial system have to be known.

With the invention two problems can be taken care of, which occur during the establishment of the models and therefore during the modeling. That is the treatment of the variant variety on the one hand and the possibility of the system-overlapping diagnosis on the other hand.

A number of different variants exist for one motor vehicle type in one embodiment. There are for example diesel systems with different engine sizes with and without turbo charger and so on for one motor vehicle type of a certain series. But the basic construction of these diesel systems is identical. If the model of each variant is now created separately this causes an enormous modeling effort. A further disadvantage is that a model of a special variant only applies and can only be used for this one variant. With the invention modeling mechanisms can be described by generating the common modules or abstracts, which minimize the effort and enable a reusability. Furthermore a system-overlapping diagnosis can be carried out.

By providing the invention it is now possible that model based diagnosing tools support a system-overlapping diagnosis even if the systems are not completely modeled at the same detail degree. Furthermore a hierarchic structuring is realized at the modeling with the aid of the invention.

Therefore a limited calculating effort is required so that it does not increase exponentially to the size of the model. Furthermore a modularization of the models is possible. A maintainability of the model is also given.

For providing the modeling it is provided that the models are present in one modeling language. A modeled unit has generally input and outputs, so-called ports. A relation between units is described by relations, behavior charts or equations with the aid of the modeling language. The relations in a model usually contain parameter, which can also be adjusted in the range of the modeling. During the relay of partial models for example of components or sub-systems the term of the material has become prevalent. Materials are transported between and also through components as simple units. Materials provide attributes, which characterize amongst others the condition of the materials and which can be changed as a module during the transport through a component or a sub-system. Air is used as material in one example, the adjoining attributes are temperature, pressure and humidity. The relay of partial systems and the modeling of the materials takes also place with the aid of the modeling language.

For a treatment of the variant variety abstract models are used. The abstracts or modules can on the one hand be created automatically from available models and on the other hand manually. At automated abstraction processes at least two models are required. The aim of an abstraction algorithm can be amongst others to detect commonalities and differences in the models. The foundations for this evaluation are previously specified metrics. A metric can for example evaluate the structure similarity of components by examining the number, the position and the used material of the ports. If two components correspond in all criteria at all ports, this component can be taken entirely into the abstract model and therefore the common model or abstract. If there are differences, only the commonalities are taken over at first, before the differences, which concrete the variant, are considered subsequently. Rules can also be specified here, which dissolve possible conflicts at dissimilarities. The metrics that are used for the comparison generally strongly depend on the application field and are usually explicitly specified beforehand at an application.

Further advantages and embodiments of the invention arise from the description and the attached drawing.

It shall be understood that the previously stated and the subsequent characteristics can be used not only in the stated combination but also in other combinations or alone without leaving the scope of the present invention.

SHORT DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example for an abstraction process that is carried out within the scope of a first embodiment of the procedure in a schematic illustration.

FIG. 2 shows an example for an aggregation of partial systems over external ports that is carried out within the scope of a second embodiment of the procedure in a schematic illustration.

EMBODIMENTS OF THE INVENTION

The invention is illustrated with the aid of embodiments in the drawings and is described in detail in the following referring to the drawings.

One aspect of an embodiment of the procedure according to the invention is schematically illustrated with the aid of FIG. 1. FIG. 1 shows thereby two sub-systems 2, 4. Each of these two sub-systems 2, 4 comprises first components 6, which are connected with each other over connecting points and thus create a common structure due to an identical construction, which is extracted and thus described as common module 8 in the range of a first abstraction step 10. It furthermore results from FIG. 1 that the first sub-system 2 provides a second component 12 and the second sub-system 4 provides a third component 14. Therefore both sub-systems 2, 4 have the first components 6, which are construed within the common module 8, and the summarized units in common. The two sub-systems 2, 4 distinguish themselves from each other by the second and third component 12, 14.

Within the scope of a second abstraction step 16 it is possible to create a new, third sub-system 18 based on the common module 8. This third sub-system 18 comprises also the common module 8 with the first components 6 that are connected with each other over connecting points. The third sub-system 18 distinguishes itself from the two first sub-systems 2, 4 by an additional unit, which is connected over an additional connecting point with the module 8 and is construed as fourth component 20.

FIG. 1 thus shows a configuration of an abstraction process in a simplified schematic illustration. At first two sub-systems 2, 4 are provided, which each only distinguish themselves from each other by one component 12, 14. The remaining components 6 are identical and can be taken over into the common module 8 or abstract at a first abstraction step 10. The abstract provides therefore all commonalities of the two sub-systems 2, 4. If a third sub-system 18 has to be created, which at least provides the units of the abstract, the abstract can be used as a model in a second abstraction step 16. Only the additional concretizing characteristics of the new sub-system 18 have to be modeled. The abstraction depth is not limited here, which means abstracts and thus common modules 8 can again be abstracted. This process can be carried on as long as one wants.

At a system-overlapping diagnosis the connecting points or ports can serve for connecting components 6, 12, 14, 20, sub-systems 2, 4, 18, systems 42 or also entire models with each other. Two different types of ports have to be distinguished thereby. Internal ports are in this context internal connecting points of components 6, 12, 14, 20 or components within a module 8, sub-system 2, 4, 18 or system 42 and enable exclusively connections of these internal components with each other. The second type of connections are so-called external ports. They create exclusively connecting points of a sub-system 2, 4, 18 with other external structures, usually systems, sub-systems 2, 4, 18 or components 6, 12, 14, 20, they are usually the input and outputs of the sub-system 2, 4, 18 and the hey to a system-overlapping diagnosis. The main condition of the relay of sub-systems 2, 4, 18 is the hierarchic structure possibility of the modeling language.

The smallest unit at the modeling is a component 6, 12, 14, 20 and can only provide external ports or connecting points. A connection of several components 6, 12, 14, 20 results in a sub-system 2, 4, 18 or system, common available structure are summarized as common modules 8 within such sub-systems 2, 4, 18 or systems. As mentioned before the relay can only be provided over external ports.

FIG. 2 shows an exemplary relay of components 30, 32, 34 with sub-systems 36, 38, 40 and a system 42 in a schematic illustration, furthermore a hierarchic arrangement of the system 42, the sub-system 36, 38, 40 and the components 30, 32, 34 is shown.

A first sub-system 36 comprises thereby six components 30 as units, which are connected with each other within the sub-system 36 over internal connecting points or ports. The second sub-system comprises five units that are construed as components 32, which are also connected with each other over internal connecting points. The third sub-system 40, which provides six units that are construed as components 34, is structured in a similar way, whereby the components 34 of the third sub-system 40 are also connected with each other over connecting points.

In a lower plane in FIG. 2, in which the three sub-systems 36, 38, 40 are illustrated in detail with their corresponding components 30, 32, 34, also external connecting points or external ports can be seen besides the internal connecting points, which connect the individual components 30, 32, 34 within the corresponding sub-system 36, 38, 40 with each other.

By summarizing the sub-systems 36, 38, 40 the system 42 is created, whereby the sub-systems 36, 38, 40 are now connected with each other over the external connecting points. In a middle plane of FIG. 2 the details of that system 42 are illustrated, while the system 42 is illustrated as a compact unit with its own external connecting points in an upper section of FIG. 2.

The components 30, 32, 34 within the sub-systems 36, 38, 40 are only illustrated in the lowest plane, which provide only external ports in their initial form. The first sub-system 36 is now created by connecting the corresponding components 30 manually. The remaining, not connected ports of the components 30 are subsequently explicitly declared as external ports, so that the first sub-system 36 has seven external ports, over which a relay with other sub-systems 38, 40 can take place, this applies analogously for the second and third sub-system 38, 40. The system 42 shows the connection of the three sub-systems 36, 38, 40 and provides also seven external ports.

The external ports can become internal ports during a relay on the next higher plane in the range of an upwards- or bottom-up consideration 44. That takes place for example when connecting the three sub-systems 36, 38, 40 to the system 42. The lowest external port of the second sub-system in FIG. 2 in the lowest plane become an internal port in the middle plane after the connection with the system 42, so that the second sub-system 38 can be connected over this port with the third sub-system 40. In the range of a downwards- or top-down consideration details and thus units of superior structures are clarified during the descent from a higher into a lower plane.

With the aid of an abstraction algorithm commonalities can be extracted from existing model elements for example the sub-systems 36, 38, 40 in order to create an abstract. This abstract or common module can be used as model for a new variant of a variant variety.

A system-overlapping diagnosis is usually thereby achieved, in that the elements of a model provide internal and external ports and can only be connected with each other over external ports. It is thereby immaterial how detailed the individual sub- or partial systems are modeled, which illustrates a major difference to the present approaches.

The abstraction process can be triggered manually in the modeling software by clicking on the corresponding symbol.

Internal and external ports can be illustrated by different colors in a modeling software. 

1.-11. (canceled)
 12. Procedure for detecting leakages in a tank system in particular in motor vehicles, wherein the presence of leakages is assumed from pressure changes in the tank system as a reaction upon pressure deviations that are caused from the outside, wherein the influence of the temperature in the tank system is considered by detecting an expected pressure change in the tank system for a default leakage size depending on the temperature and by assuming the presence of leakages from the comparison of an actual pressure change with the expected pressure change, is thereby characterized, in that the following steps are comprised for detecting the expected pressure change: detection of the equilibrium vapor pressure as partial pressure of the fuel (HC) pHC_(equi) at a given temperature (step 21), detection of the deviation between pHC_(equi) and a modeled partial pressure pHC (step 22), detection of a vaporization rate of the fuel pHC_(equi) (step 23) from the deviation between pHC_(equi) and pHC, determination of the net-vaporization rate (step 24) as a difference between the vaporization rate and a modeled HC-leakage current, integration of the net-vaporization rate over a time (step 25) for determining the vaporous HC-mass, determination of the modeled partial pressure pHC from the vaporous HC-mass at a given volume (step 26) and a given temperature (step 27) and determination of the modeled HC-leakage current by means of the modeled pHC at a given partial pressure of the air pair at a default leakage size (step 28).
 13. The procedure according to claim 12, wherein the default leakage size corresponds with a leakage with a diameter of 0.1 mm to 0.8 mm, preferably 0.3 to 0.6 mm, in particular 0.5 mm.
 14. The procedure according to claim 12, wherein the temperature is measured and/or estimated in the tank system.
 15. The procedure according to claim 12, wherein the course of the vaporization pressure of a fuel is considered as a function of the temperature.
 16. The procedure according to claim 15, wherein the courses of the vaporization pressure are stored for at least two fuels as a function of the temperature and one course is selected and considered.
 17. The procedure according to claim 16, wherein the selection of a course takes place by the consideration of factors, which allow a conclusion of a certain fuel, wherein the factors preferably are fuel-volatility, fuel quality, exhaust gas values at dynamic load changes, engine behavior during a start, season, geographic place and/or surrounding temperature course.
 18. Procedure according to claim 12, wherein the pressure variations that are coming from the outside are natural pressure deviations.
 19. The procedure according to claim 12, in that the pressure variations that are caused from the outside are caused by separate pressure sources.
 20. Computer program, which carries out all steps of a procedure according to claim 12, if it runs on a computer, in particular a control unit.
 21. Computer program product with a program code, which is stored on a machine-readable carrier, for implementing the procedure according to claim 12, if the program is carried out on a computer or a control unit. 